Quantifying hospital environmental ventilation using carbon dioxide monitoring - a multicentre study.

The COVID-19 pandemic has highlighted the importance of environmental ventilation in reducing airborne pathogen transmission. Carbon dioxide monitoring is recommended in the community to ensure adequate ventilation. Dynamic measurements of ventilation quantifying human exhaled waste gas accumulation are not conducted routinely in hospitals. Instead, environmental ventilation is allocated using static hourly air change rates. These vary according to the degree of perceived hazard, with the highest change rates reserved for locations where aerosol-generating procedures are performed, where medical/anaesthetic gases are used and where a small number of high-risk infective or immunocompromised patients may be isolated to reduce cross-infection. We aimed to quantify the quality and distribution of ventilation in hospital by measuring carbon dioxide levels in a two-phased prospective observational study. First, under controlled conditions, we validated our method and the relationship between human occupancy, ventilation and carbon dioxide levels using non-dispersive infrared carbon dioxide monitors. We then assessed ventilation quality in patient-occupied (clinical) and staff break and office (non-clinical) areas across two hospitals in Scotland. We selected acute medical and respiratory wards in which patients with COVID-19 are cared for routinely, as well as ICUs and operating theatres where aerosol-generating procedures  are performed routinely. Between November and December 2022, 127,680 carbon dioxide measurements were obtained across 32 areas over 8 weeks. Carbon dioxide levels breached the 800 ppm threshold for 14% of the time in non-clinical areas vs. 7% in clinical areas (p < 0.001). In non-clinical areas, carbon dioxide levels were > 800 ppm for 20% of the time in both ICUs and wards, vs. 1% in operating theatres (p < 0.001). In clinical areas, carbon dioxide was > 800 ppm for 16% of the time in wards, vs. 0% in ICUs and operating theatres (p < 0.001). We conclude that staff break, office and clinical areas on acute medical and respiratory wards frequently had inadequate ventilation, potentially increasing the risks of airborne pathogen transmission to staff and patients. Conversely, ventilation was consistently high in the ICU and operating theatre clinical environments. Carbon dioxide monitoring could be used to measure and guide improvements in hospital ventilation.

Ondansetron, an antagonist of 5-HT3 receptors, in the treatment of antineoplastic drug-induced nausea and vomiting in children.

The aim of this study was to evaluate the efficacy and safety of ondansetron, an antagonist of 5-hydroxytryptamine type 3 (serotonin 3) (5-HT3) receptors, in controlling nausea and vomiting induced by antineoplastic therapy in children affected by cancer. Six patients affected by nausea and vomiting due to antineoplastic drugs were treated with ondansetron (4 mg/m2). Urinary samples for the assay of serotonin and 5-hydroxy-indoleacetic acid (5-HIAA) were collected 24 hr before antineoplastic drug treatment, 24 hours after the start of antineoplastic therapy and, 24 hr after the start of ondansetron therapy. All patients were affected by nausea and vomiting within two to four hr after the antineoplastic treatment. Urinary concentrations of serotonin and 5-HIAA were higher and statistically significant (P < 0.01) with respect to basal values. Treatment with ondansetron significantly reduced the number of episodes of nausea and vomiting, as well as the urinary values for serotonin and 5-HIAA.